Water Resources Research Act Program

Details for Project ID 2009AZ313B

Mercury Source Fingerprinting in Arid Lands Aquatic Ecosystems

Institute: Arizona
Year Established: 2009 Start Date: 2009-03-01 End Date: 2009-12-31
Total Federal Funds: $10,585 Total Non-Federal Funds: $21,950

Principal Investigators: Paul Gremillion, Michael Ketterer

Project Summary: Mercury (Hg) is well-known as a global pollutant; its main source is coal combustion, and deposition of Hg into aquatic systems and landscapes produces subtle neurotoxic effects in vertebrates at low concentrations. Identifying Hg sources and unraveling their relative contribution to the Hg inventories in water, soil, sediment, and biota remains an elusive problem despite four decades of environmental studies of Hg. Recent work by several groups, however, indicates that Hg exhibits small variance in its stable isotope compositions; this variance is source-related and can potentially be used to understand sources, transport, and biogeochemical cycling of Hg. Research in Hg isotopes is not well developed, but is the subject of intense interest among several research groups. At NAU, the PI (Gremillion) has been studying Hg in the Arizona environment for several years, and has received research support from the Arizona Department of Environmental Quality (ADEQ). This agency is responsible for promulgation of regulations, and development of policies relevant to Hg concentrations in fish, soil, and lake sediments. ADEQ needs to determine contributions of various Hg sources in the Arizona environment; for example, point source controls on Arizona power plants may be moot if the major fraction of the Hg inventory is derived from Asian emissions. This proposal requests $10,585 in federal funds, matched with $25,000 in non-federal funds to develop the capability of measuring small differences in mercury isotope compositions using an instrument available in-house known as a multiple collector inductively coupled plasma mass spectrometer (MC-ICPMS). A MC-ICPMS system has been operation at NAU as a result of a 2001 NSF Major Research Instrumentation award to the Co-PI (Ketterer). The PI will work with the Co-PI and an external expert in developing Hg isotope measurement capabilities; these will be applied in a proof of principle fashion to two Arizona lakes exhibiting large recent increases in Hg deposition. As a result of this project, it will be possible for the PIs to generate meaningful preliminary data needed for writing fully developed, competitive proposals to Federal agencies such as NSF and DOE. The entire federal request will be dedicated to training a graduate research assistant, Edyth Hermosillo, as part of her master of science research in the Environmental Sciences program at Northern Arizona University. The increased scope of work afforded by the combined federal and non-federal funding will enable us to employ several undergraduate research students and will result in at least one capstone research project.